Hi Don,
I agree with you and Joe on the design methodology, but a significant number
of of our clients use the extend existing cross fall method of design. Let
me go into advertising mode for ARD again where you can do it easily do it
either way.
--
Regards,
Laurie Comerford
www.cadapps.com.au
"Don Reichle" wrote in message
news:41b66370$1_3@newsprd01...
> Hey Danny;
>
> I would echo Joe, but also ask if the outcome is to keep the existing
> conditions (which bring to mind a "wash-board" effect on the passengers in
> the vehicles traversing this road) or to improve the condition?
>
> If the former, you can painstakingly emulate this condition with separate
> profiles attached to the transition alignments for your widening. I use
> the
> term painstakingly, because you will spend a great deal of time with Excel
> or QuattroPro attempting to report the varying cross-grades at each 25
> foot
> station of the controlling alignment. And God forbid if you need to
> account
> for intersections through this corridor!
>
> If the latter, then I would find whichever of the two edge conditions
> (read
> rights of way) create the condition which will enable you to adopt a
> normal
> crown section for your locality, providing a smooth ride for the vehicle
> occupants. This edge condition would be the one which provides the closest
> daylight line to the right of way in question. That way you keep the
> impact
> of retrofit grading to a bare minimum. And at least you can account for
> your
> intersections more reasonably because you will have only one cross-grade
> to
> deal with through each one.
>
> HTH
>
> --
> Don Reichle
> "King Of Work-Arounds"
> Barghausen Consulting Engineers
> Kent, WA USA
> LDT3 - SP1/CD3 - SP1
> On WIN2K SP4
> Dell 1.6 Ghz P4
> 512MB RAM
> NVIDIA 32MB AGP
>
>
> "Joe Bouza" wrote in message
> news:41b61930$1_3@newsprd01...
>> Hi Danny,
>>
>> I think the best you can do for this type of condition is to locate
>> transition points and draw 3dpoly lines to approximate the existing cross
>> slope. Then you can extend thes 3dpoly lines to "extend" the existing
>> condition. But, I you are widening the road why not use a constant, or
> more
>> mathematical cross slope ?
>>
>>
>> Joe
>>
>>
>> "DannyCounts" wrote in message
>> news:3073171.1102382002736.JavaMail.jive@jiveforum2.autodesk.com...
>> > think about the crossgrade between the centerline profile of an
>> > existing
>> > road and a profile running through the top surface of the same road at
> any
>> > given offset, say 12'. Again think about the cross-grade between those
> two
>> > profiles. If it is an existing roadway, chances are the cross-grade
>> > varies. Is there a way to project the varying crossgrade between those
>> > profiles further out to any given offset? I can build a surface of the
> 3D
>> > polys representing these two profiles, I also tried extending the TIN
>> > lines, but then they begin to cross and I don't know if that is
>> > representative of what it should be doing. Is there any other way to
>> > accomplish this?
>>
>>
>
>